I haven't trolled through all the other posts, so apologies if this point has been covered before.
Having flown that route many times myself, (and in a 777, not that that has anything to do with it), I'd be very surprised to find there were not quite a large number of eye (or at least ear) witnesses to the aircraft hitting the sea. The number of fishing boats in those waters beggars belief. Overflying that area at night, there are so many fishing boats, each with a light, you could be forgiven for thinking you were overflying a huge city.
If I'm correct, it will probably be a day or two before any such eye/ear witnesses return to port.